Repeated “java.lang.IllegalStateException: Cannot forward after response has been committed” errors with Grails and Tomcat

Question

Please see my post on the Grails user mailing list. Essentially, I get the error "Cannot forward after response has been committed" with Grails 2.x after every few requests. This happens for all types of URLs, controllers, GSPs, CSS files, JS files and even image files. I have tried Grails 2.0.0 and Grails 2.0.1 with Tomcat 6.0.35 and Tomcat 7.0.25 on Windows XP 32-bit, Windows 7 32-bit and Centos 64-bit. The error comes up on all these combinations.

As I have mentioned in my post, there are no response.redirect or response.forward statements in our code. This is causing severe problem on our production application so need help in determining what else can be looked at to get to the bottom of the problem.

Answer 1

This has been solved. In one of the controllers in the application, response output stream was being directly written to but not closed explicitly after the operation was over. It seems Tomcat and Jetty recycle response objects. When a response object that did not have their output stream closed earlier was recycled for a future request and redirect was performed on it, the redirect would fail.

The code has been changed and the error has disappeared now. The lesson learned is that any time such an error occurs, scan the entire code base for direct access to response output stream and close output stream responsibly before existing controller methods.

Answer 2

You should create a new grails application and move the controllers, domains and etc yourself rather than grails update.

When you do that also make sure you look into the configuration files of grails.

Also take a look at what plugins you have.

Also, when moving the files, try out the application once in a while when it is possible, and perhaps you can detect when the error arises. Start out by trying it in your most basic controller and see if the error is there then as well.

Good luck.